Originally a solo singer recording under the name Frankie Valley, he joined the Variatones in 1954. They made their first records as the Four Lovers but achieved lasting success when they became the Four Seasons in 1962. Although he was lead singer with the group, Valli also had a solo recording career, starting with "(You're Gonna) Hurt Yourself" in late 1965. He scored a million-seller in 1967 with "Can't Take My Eyes Off You". From the same album came further US hits, "I Make A Fool Of Myself", and "To Give (The Reason I Live)" while "You're Ready Now" was a reissued success in Britain in 1971.

Valli and producer Bob Gaudio now set up a dual career, with Valli recording for Private Stock and a new Four Seasons group for Warner Brothers Records. Valli had his first solo number 1 in 1975 with "My Eyes Adored You", followed by "Swearin' To God" and a revival of Ruby And The Romantics' "Our Day Will Come". In 1978 he sold two million copies of the Barry Gibb -composed theme song from Grease. The follow-ups, "Fancy Dancer" and "Where Did We Go Wrong" (a duet with Chris Forde) sold poorly and in 1980 Valli had a series of ear operations to cure his increasing deafness. He subsequently rejoined the Four Seasons and enjoyed further success when "Big Girls Don't Cry" was included in the movie Dirty Dancing. In 1990, the Four Seasons were inducted into the Rock And Roll Hall Of Fame, and for the rest of the decade Valli continued to lead the group on the lucrative oldies circuit.